#include <stdio.h>
extern void test();
extern struct structS
{
    int a;
    int b;
} structTest;
extern enum enumE {
    BLACK,
    WHITE
} enumTest;
extern union unionU
{
    int a;
    char b;
} unionTest;
int main()
{
    test();
    printf("StructTest.a=%d,StructTest.b=%d\n", structTest.a, structTest.b);
    printf("enumTest=%d\n", enumTest);
     printf("unionTest.a=%d\n", unionTest.a);
    printf("extern test");
}